Pressure compensator for pneumatic tires



Aug. 18, 1936. H. H. PARKER PRESSURE COMPENSATOR FOR PNEUMATIC TIRES 2 Sheets-Sheet l Filed April 9, 19:56

INVENTOR. Howard Hen/y Paf/mf im@ ATTORNEY.

Aug. 18, 1936. H. H. PARKER I PRESSURE COMPENSATOR FOR PNEUMAIIC .TIRES 2 sheets-sheet 2 Filed April 9, 1936- R,r WP mw Ww ATTORNEY.

Patented Aug. 18, 1936 UNITED STATES ATENT GFFICE PRESSURE COMPENSATOR FOR PNEUMATIC TIRES This invention relates to a pneumatic tire inflating device.

More particularly, this invention relates to an inflating device in combination with a pneumatic tire and operable to inflate the tire during use so as to maintain a predetermined pressure within the tire. Y

The inflating device of this invention is not intended to compensate for leaks due to punctures or bad valve defects. It is intended to compensate for the normal loss of air pressure common to all automobile tires and to maintain substantially the air pressure in all the tires of a vehicle.

An automobile tire makes many millionsV of revolutions during its life. An inflating device, in combination with the tire, is subject to severe wear. It is desirable to reduce the wear on the inflating device to only such as is necessary for maintaining the tire fully inflated. It is an object of this invention to provide a novel tire inating device, in combination with a vehicle tire, adapted to undergo substantially no actuation when the tire is fully inflated. I

The inflating device of this invention is intended to pass through a cycle of operation with each revolution of the tire. To actuate the device with every tire revolution would impose severe wearV on the device. It is an object of this invention to provide a novel tire iniiating device which operates through a complete cycle with each tire revolution at moderate speeds of vehicle move'- ment only, and which ceases to function at high speeds, when a tire is fully inflated, and also When a tire is under-inflated to a predetermined degree,

thereby minimizing undue Wear.

Only a small partof the circumference of a tire, an automobile tire for example, touches the pavement at any time. Where the deformation of the tire, due to its under-inflated condition, upon engagement with the pavement, is utilized for causing operation of the inflating device, a large force of relatively short duration becomes available for actuating the device. The duration of the force is short because, even at moderate speeds, any particular portion of the tire is in contact With the pavement for only a small fraction of a second.

Where the fluid pressure within the tire, eX-

erted upon a diaphragm, the movement of which is resisted by air within the device, is used for actuating the inating device, that force is small due to the fact that a dilerential between forces derived from fluid pressures, only is available.

Also, that force is elastic in its nature and tends to be slow in operation.A The transfer of air, drawn from the atmosphere into the iniiatingY device, to the interior of the tire may proceed slowly and under moderate force with advantage.

.It is an object of this invention to provide 5 a novel tire inflating device actuated by the large force associated with tire deformation and actu-V ated by the small force associated with fluid pressure differentials across a diaphragm, the large force acting upon the device for only the period l0 of timeY required fer a particular small area, less than the area of road contact, to pass through road contact, the small force acting upon the inflating device throughout the kwhole of the remainder of the period of time of a tire revolution. l5 It is also an object to utilize the large force, of short duration, to effect intake of air from the atmosphere into the inating. device and to utilize the small force, of relatively long duration, to effect exhaust of air from the device into the 20 tire interior.

It is an object of Vthis invention to provide an inflating device of the diaphragm type thatl is small and light, that is arranged Within the pneumatic tire, that has no protruding parts 25 Which would jab, cut or tear an inner tube or tire casing if the tire should become flat while the vehicle is in operation. It is an object of this invention to provide a novel tire inating device operable to inflate 30 a pneumatic tire to a standard pressure, which is operable on deformation of an under-inated tire, which undergoes little or no actuation upon normal deformation of a fully inflated tire, Which is actuated but slightly by deformationV of a fully 35 inflated tire when the vehicle is overloaded. Y

Other objects and advantages of the present invention will appear in the following detailed description taken in connectiion With the accompanying drawings in which; 1 l

Figure 1 is a view in cross section, of the tire inflating device in combination with an auto--Y mobile tire.

Figure 2 is a view, in cross section, of the device shown in Figure 1, in another position of 45 actuation.

Figure 3 is a detailed View, in cross section, of a modied form of an inflating device.

Figure 4 is a detailed view, in cross section, of another modification. 50

The inflating device operates by intake of air from the atmosphere to an air pocket within the device and exhaust of air from the pocket into Ythetire interior. A valve separates the atmosphere and the air pocket. A diaphragm sep- 55 arates the air pocket 'andthe tire interior. The valve is constructed to remain closed and a presfrsure differential across the valve, due to atmospheric Vpressure on one sideY of` the Valve .and less than atmospheric pressure on the other side is required to open the valve to admit air into theV air pocket. This differential'pressure across the l. Y valve,e'ffective for actuating it, is a minimum force relative to which other actuating rorcesY must be larger.'

The pressure diiierential across the valve is created by displacement of the diaphragm to re-` duce the air pressure within the air pocket. That movement of the diaphragm is against the fluid pressure in the tire interior. The diaphragm is much larger than the valve. The force which must be exerted on Vthe diaphragm, toY open the air intake valve, is many time larger Vthan'the pressure diflerentialacross the valve.

The force for. displacing the diaphragm to open Vthe intake valve is derived from the fluid pressure in the tire interior. `A description of 'the structure for providing that force follows. Y

Referring to Figure 1, the rim of an automobile wheel is indicated at I, and consists of annular well v2, shoulder 3, and ange 4. An automobile tire5 is mounted on the rim I, the beadportion `6 lling shoulder 3 withinthe flange Il.V Thek tire is provided with the inner tube 6. f

The Vcontour ofthe tire, as illustrated in'Figure 1, may be regarded as either of two conditions.

It is the shape of some, portion of the tire, not in Contact with theVV road whenthe tireV is in under- Y inflated or in inilated condition. f j Y The force for actuating the diaphragm onV airintake stroke is exerted through connection mem-V bers 1. The members T, or their equivalent, may be mounted in combination with the tire in a variety'of ways', within the purview of this invention. As shown; the members I are arranged betweenthe inner tube BVand theinner wallV ofV the tire casing y5. They may be adhesively united y Members 'I are of a shape to conform to the or .vulcanized to the outside of the'inner tube and form a 'unitwith the inner tube. connections 3, desirably of fabric, lead from` the members-1 tothe inliating device. The ilexible Vconnections 8V eXtendthrough-apertures 9 in theY inner tube t. The members 'I closethe apertures 9V so that leakage throughcthose apertures cannot occur.

. side-walls ofthe tire,leach tapering from thin n side-walls of the tire in a.circumferentiaLdirec# 7; edges toa comparatively massive central por-Y tion, to distribute Ythe load, exerted on the connections 8, throughoutthe wholegarea of the members. The members -'I may extend'along the Y c tion, for a length considerably Ygreater than the Y Y width, as shown in` Figure 1. 60y

The' air pressure Within the tire'acts, through the wallrof the inner tube, on themembers,

Vthe latter being conned by the tire casing. The

fluid pressure on the members I provides'the Vforce for actuating the diaphragm through air, in take displacement. The fluid pressure onrthel members 'I is .the same as that upon the dia- .Y phragm; To provide adequate force,V the members V'I are each large enough to afford an eiiectivek pressure area, approximating or greater than'the VYeffective pressure area of the diaphragm.V The Y resultant-of the forces from each member 'I approximatesV orrris greater than twice vthe force necessary to actuate the diaphram on intake stroke; i The particular ratio of Vthose forces is not of the essenceof the invention; it being imjoint I@ decreases.

Flexible portant only that the force exerted through members 1 be adequate.

When -the tire casing deforms,V the members Y follow the movement of the casing. The members are cntrained to follow that movement by the fluid pressure within the inner tube. ,When the tire is fully'inflated, or when theiniiating device is out of road contact position, the parts are in the position illustrated in Figure 1, Where the distance between members 1 is a minimum. When the tire is under-inflated and when that portion Vof the tire, which is combinedrwith the inlating device, engages the roadthe tire spreads to la form such as that illustrated in Figure 2. Such deformation of the tire casing moves the members I a distance apart greater than that shown in Figure l. The Vconnections 8 join ras indicated at I 0. The relative lateral movementV of the members 1 draws the joint II) downward- 1y, as shown in Figures l and y2, so that the dis` tance between the level of the members I and the I the joint it and theV members 'I are thought of as being the corners of a triangle, the relative lateral movement of the` members 'I causes the joint I0 to approach the side of the triangle between the members 1. 'I'his movement is the consequence of the arrangement of members I at substantially opposite locations relative tothe center of the tire treadY and tov Y the location of joint I0, the members 1 being arranged at proper locations with respect to tire tread and Vside walls, the arrangement of those `parts shown in Figures 1 and 2, isillustrative of such proper locations of the joint and the members. Variations in those locations may be made to adapt the device to various tire casings, to

vary the strokeof diaphragmmovement and to .accomplish otherobjectives later to be described. Y

Flexing of the tire casing, due to its underinilated condition, also causes the tire tread, and

the members 'l as well, toapproach the rim I. The amountof movement of joint I0, due to the relative lateral movement of members 1, maybe tions relative to the members 'I. Such ar location may be chosen, as illustrated in Figures 1 and 2, so that the movement of joint YIIL'due torrelative variedby arrangingY the Vjoint YII] at various locaV Y lateralrmovement of membersrl, willjbe greater fr ing substances or inserts. The base I I is secured v to the inner wall of the inner tube 6 and may'Y be vulcanized in place or mounted by an adhesive Y An insert I2 forms a part of baseil E and consists of the tubular portion I3 arranged to extend from the base II through the inner tube 6, into'V Yproximity to an opening in rim I, to constituteY an air duct. i Tubular portionrl3 is ared to form the valve VVseat I4, from which the margin I5 extends laterally and is embedded in the rubber. j

'I'he material of base II, is free from the margin I5, at a region surrounding'the valve seat I4', and

is formed to provide the tongues of a valve I6. The resilience ofthelrubber forming the tongues of the valve I6 tendsto' keep the valve closed. Spring means, suchV as strip springs (not shown) embedded intherubber, may be provided to aid in urging the tongues of vthe valve I B to closed position.

An air impervious membrane I1, desirably of elastic rubber, is united with the base II at its outer margins as indicated at I8. The intermediate portion of membrane I1 is free-as indicated at I9; and the inner margins 2B, surrounding the opening 2I in membrane I1, are united to a diaphragm 22. The membrane may be connected with the Ybase and diaphragm by vulcanizing or by adhesives. This structure vconstitutes the air pocket.

Diaphragm 22 is provided with an insert 23, which may be of sheet metal, to stirfen the central area of the diaphragm. The diaphragm may be of any suitable air imperious material such as vulcanized rubber in which the insert 23 may be embedded. The diaphragm 22 is fieXible at its outer margins as indicated at 24 and fabric inserts 25 may be embedded in the material of the diaphragm to strengthen it at the edges of the rigid insert 23. The diaphragm 22 is connected as indicated at 25 to the inner wall of the inner tube 6. The insert 23 is shaped to provide a conical valve seat 21 at its center. The material of the diaphragm 22 is free from the insert 23, at a region immediately surrounding the conical valve seat 21, and it is shaped to provide the tongues adapted to engage with the seat 21 and to constitute a valve 28. The resilience of the material tends to keep valve 28 closed.

The diaphragm 22 is connected with the joint E0 by fabric strips 29, the ends of which are ernbedded in the material of the diaphragm 22, and

may extend through and engage the insert 23 so as to transmit the force from' joint I0 directly to the insert 23.

In mounting the inating device in the inner tube, parts are arranged in at position as indicated in Figure l, in which position, during operation, there is no strain 0n the parts and all 'fluid pressure acting on the diaphragm 22 is supported by the body Il. Due to the closed position of the diaphragm 22, when it is being mounted, a vacuum pocket 39 is provided between the diaphragm 22 and the membrane I1. Since the parts, when united, completely close the pocket 30 to air from either the atmosphere, the inating device, or the inner tube, no air gains access to the pocket 30. It remains a vacuum pocket at all times.

With the parts in the position illustrated in Figure l, the distance between the members 1 is a minimum and the diaphragm 22 is at rest against membrane I1 and base II. The air pocket collapses completely and the membrane ties flat against the base and the valve I6, there being no space in which residue air may remain. The connections 8 may be of such length that they are barely held taut when the parts are in the position illustrated in Figure l, there being very little strain upon the diaphragm 22.

According to the degree of under-inflation, as the part of the tire casing illustrated in the drawings engages the road, relative lateral movement of members 1 occurs and actuation of the inflating device takes place. When the diaphragm is at rest, fluid pressure within the inner tube acts upon the whole face of the diaphragm and is not resisted by fluid pressure on the opposite side, the diaphragm being supported by the base II and there being very little air in the vacuum pocket 30. The area of the diaphragm 22 and the iiuid pressure within the inner tube are such that a considerable force is requiredto displace the diaphragm' downwardly, as shownin thev drawings, against the fluid pressure. As the portion of the tire shown in the drawings passes the roadcontact position,v the tire, being under-iniiated, flexes under the load of the car. Mem*- bers 1 follow the tire deformation and adequate force for actuating the diaphragm, against the fluid pressure on it, is provided by the force of the luid'pressureV on the members. This action occurs within a small fraction of a second so that comparatively large force is exerted with a jerk through the connections 8 on the inlating device. The members 1 are large enough so that the air pressure exerted upon them is adequate to overcome all inertia of the moving parts while' transmitting the force through the connections 8 for displacing the diaphragm 22.

When the diaphragm 22 is displaced, atmospheric pressure acts to open the valve IB and air entersthe air pocket formed by'membrane i1, base I I, and diaphragm 22. Fluid pressure within the inner tube maintains the valve 28 closed. The actuation of the inflating device, at slow and moderate speeds of vehicle travel, creates a differential of pressure across the valve I6 so that it opens to admit air. Then, the valve I6 resumes its original closed position to close the air pocket to the atmosphere.

During the remainder of the revolution of the wheel, the tire casing assumes the position as shown in Figure l and all tension is relaxed in the connections 8 so that they may hang loosely so long as the diaphragm remains in displaced position. The uid pressure within the inner tube acts upon the face of the diaphragm 22 o tending to force the air from within the membrane l1 through valve 28 into the inner tube. The effective area of diaphragm 22 is greater than the eective area of the air pocket, due to the'difference in size of those parts and due to the presence of vacuum pocket 30, so that a force is exerted on the diaphragm tending to restore it to the collapsed position. The result is that the iluid pressure within the air pocket is raised considerably above that 4obtaining within the inner tube 6. Consequently, air is forced out of the air pocket, through the valve 28, and into the tire interior.

Up to a certain limit, the actuation of the inflating device, consequent upon relative lateralY displacement of members 1, increases with increasing degree of under-ination. Consequently, the greater the under-inflation, the greater the inflating action of the device. As the air pressure within the tire increases, the magnitude of relative lateral displacement of members 1 diminishes and the inlating action of the device grows progressively less. Thus, the device operates to inflate the tire most rapidly when the need is the greatest and the inflating action tapers oii as the air pressure approaches standard.

Two actuating forces are involved in the operation of the iniiating device. One force, derived from the fluid pressure within the tire upon connection members 1, is large. The other force, derived from the diierential between iluid pressures acting on the diaphragm 22, is much smaller, The device of this invention uses those forces most effectively, the difference in magnitude being taken into account.

There are two alternate operating positions of the inflating device relative to the tire; road contact position of that part of the tire adjacent to members 1, and out-of-road contact position of that same part." In a single revolution of an '7 automobile tire, the time; of Y road contact of that j part of theV tireisabout 5% Vof the period of .revo-- 'lution, Vwhile the time of non-road contact movement of the same part is about 95% of the period of revolution. jThus, thertwooperating positions have time periods in the ratio of about one to v.For exampldconsider theaction of atire on an .Y automobile traveling about twenty milesper hour.

e' ,Thegtime duringwhich'thefsame part of the tire Y '15 The period ofV revolution of :a tire of common size Yisin the orderofone-fourth of one second. The

time of road contact of the actuating partV of the tire is of the order of one-.eightieth ofone second.

is out of roadV contact'is in the order ofrone-fourth ofV one second'less the time of Vroad contact. n

VThe twol actuating forcesare used most eiec` tivelylby causing the large force to actuate Vthe inflating deviceduring the shorter time and by ing the longer time.

causing thesrnall forcectoactuate the device durso operates. The'arrangement ofthe members 1 at opposite sides of thejcenter of the'tire tread Vand the operation there'oLbefore described, upon tire deformation during roadl contact, placesthe larger of thetwo forces intooperationfor actuatingthe Ainiating devicefand that event occurs incidentY to and only `during movement of fthe Y. members 1 through road contacting position. As

soon asthe members 1 leave road contact position, the fluid pressure within the tire, `acting on diaphragm 22, becomes effective for the remain- Yder ofthe tire revolution.` Y Y w YThis modeoi operationrof` artire inflating device, whereby a large `force acts suddenly anda comparatively small force acts for a comparatively great period of time, bothY forces being delrived from thefluid pressure in the tireY interior,

the forces being initiated by and being under the control of the deformationof the tire at road contactfis believed to be' new to this art.

' YThe foregoing description is concerned with Vthe operation of the device of thisinvention inconf- AFigu'rerS. tional constructionV and has a base 4|, integral nection with a moderatelyV under-inflated tire, loaded within normal limits, and moving at moderate ratesof speed. TheractionsV incident upon high speed travel, Very slow speed travel, excess under-inflation, excessively. loaded tires, Vand standard pressure Vinithe tire, will be described Y subseoluently.r Y A' modified form of the invention is illustrated inFigure 3. The iniiating device maybe entirely independent of the usual valve stern for inflating ai tire, as in Figures l and V2, Vorrit may be in connection with such Y.a valve stem as shown in The valve stem 40 may beY of conventherewith, to Ybe arrangedwithinthe inner tube.

AY nut 42 may-be provided: for securing the valve` stemV tightly tothe rim 43; The rigid 'baseY 4I of the'valve stem affords a convenient'base for the iniiating device.' `The base 4l maybe eni-v 'Y bedded in vulcanized Vrubber 44, if desired, to

1 but highly flexible.

aiiord suitable connectingmaterial for securing the inating device to the base. A iiexible bag 45, which may be of rubberized fabric, is secured to the base 4| as indicated at, there being an aperture in the fabric within the margins where therbag is secured'to the base 4l. The bag 45 may be made of two halvesunited ata seam 41. The material of the bag 45 may benen-extensible diaphragm 48 as indicated at 49.Y Diaphragrn48 may consistof a rigid insert, of metal or thek like, arranged betweenY sheets of rubberized fabric 5l,

Theldevice of this invention Y The'bag l5 is securedto a whichiextends beyond the margins of' thev insertV 5G to form iiexible portions52 joined to the ibase '4I as'indicated at 53.l 'I'he space 54 between the baseV 4| vand the diaphragm 48,Y and outside of bag 45 is substantially empty'of air and constitutes Va vacuum pocket. Thediaphragm Vdilis connected with the` tire lbyilexible strips 55 leading to joint 56, in the same manner asv illustrated in Figures 1 and 2. The bag 45 is an air pocket Yas specified in the claims. v Y Y The stem 40 of thefvalve is provided with a sleeve 51 Ythreaded for insertion and removalv intoV and fromY the stem. The sleevev 51 :carries the; A valve seat59V is arranged in` the lower end of the tube,51 and is engagedY by a Y valve insides 58.

Valve 60. V'Stem 6| extends through the seat 53 to place the spring above thevalve and valve seat, and to place the valve at the'end of stem lli). It is desirable Vto arrangethe valvey atthe end Yor the stem 4G so that,when theinilating Y device is moved to closed position, there will be no air space within Vthe valve stem on the sider of the valve adjacent'to' the air pocket.

The operation ofthe device in Figure 3 is Ysimi` lar to that of Figures l and 2. When road contact of that portion of an under-inflated tire, Y

Vwhich is connected for operation of the inflatin'g device, occurs, the spreading action of the tire casing causes the diaphragm 48 to be jerked Y downwardly, as shownein Figure 3, to move Vthe Vparts to theV position illustrated in Figure 3.V

Whenthat action occurs, atmospheric pressure" opens the valve 'and air enters the .air pocket or bag 45. This action occurs Yquickly and the valve 6l) closes an instantlaterto trap theV air inV the bag 45. When the operating part ofV the Ytire casing passes road contact position, the force upon the diaphragmY 45, throughstraps 55 is relieved, and for the remainder of the revolution` tube acts upon the diaphragm 48 to compress the air in bag. 45.

parts and due to the presence of Vthe vacuum pocket 54.1 Y I r:. l

An aperture 64,V open at all times, is provided in the diaphragm 50, and connectsV the Y"space Y Within theV bag 45 with ,the tire interior.f.The

aperture 64 replaces aV valve, such as valvef28,1

The effectivekare'a of the dia` phragm 48 is greater than thereiective area ofl Y the bag-45, due to the diiierence in sizes of those of the wheel, the fluid pressure within the inner` Y Figure 2, and 'is desirable vbecause ofits .effect onthe operation of the -device of Figure 3 when operating at high speed of .vehicletraveL As the speed of travel of Ytheautomobile or other vehicle increases,V the time interval -be'- Y tween successive Vroad contact of theractuating part of the tire decreases. At high speeds, that of the diaphragm.V The device remains more or less distended, depending on the speedlof vehicle travel and the operating characteristics of the* The diaphragm may remain Ysubstantial- 'F ly fully `distended and flutter slightly `at lthat device.

position. Y

When the device of lFigures l at high speed, the action last described occurs. The pressure within the -air pocket remains Y partly reduced, in a degree depending upon the and 2 is operated Y interval becomes `too short to permit full return ,6.5

When the device of Figure 3 is subjected toV high speed operation, the aperture 64 operates greatly to relieve the strains and wear on the device. As the vehicle speed increases and the interval between diaphragm displacements by the larger of the two actuating forces diminishes, the diaphragm 43 oscillates between fully distended position and increasingly large partially distended positions. The aperture 64, being open, permits air to iow from the tire into the air pocket to establish tire pressure within the air pocket, This action takes place regardless of any actuation of the valve 6U, due to the movement of the diaphragm 48. Thus, the actuatingv force tending to return the diaphragm to initial position is reduced and the diaphragm tends to assume fully distended position where the force associated with tire deformation has minimum effect. The diaphragm flutters but slightly in fully distended position, the opposing forces on it are reduced, and wear on the device, due to high speed vehicle travel. is minimized.

At moderate speeds of vehicle travel, the movement of the diaphragm by the larger of the two actuating forces is so sudden that a reduced pressure is created within the air pocket, adequate to cause opening of the valve 5G. before air. sufficient materially to reduce the pressure differential across the valve 60, can flow from the tire through the aperture 64. The return movement of the diaphragm 4B, by the fluid pressure on it, proceedsV at a comparatively slow rate over a comparatively long period of time so that the air in the air pocket passes through the aperture 64 into the tire interior, inflating the tire.

At extremely slow speeds of vehicle travel, the movement of the diaphragm 48, on air intake actuation, is so slow that air from the tire will flow through the aperture 64 instead of the valve BEI being opened. When starting a vehicle from rest, the diaphragm 64 may be collapsed completely and, if the tire be under-inflated considerably, the rst stroke of the diaphragm may be large with consequent tendency to create large strains. The aperture 64, together with the slow movement of the diaphragm, under such conditions, relieves excessive strain on the device.

Thus, the aperture 64 acts to relieve strains on the device when the vehicle is starting, the aperture acts similarly to a valve at moderate speeds, and the aperture operates to relieve strains and wear on the device at high speeds of vehicle travel. In`addition, the provision of aperture 64 in diaphragm 48 is a simple, reliable, and enduring structure.

Figure 4 shows a further modification of the inflating device. This gure shows the inflating device of Figure 1, like the latter in all respects, except that a passage l5 is provided for connecting the space 3B', around the air pocket and between the base and diaphragm, to atmosphere. This enables that space to breathe and to eliminate any back pressure against the diaphragm. Breathing of the space 30 provides atmospheric pressure to that space when the inflating device is held in distended position due to high speed operation, as before described,.thus further reducing strainsand wear on the device. The passage 15 to the space 30 prevents accumulation of air in that space due to seepage of air through the materials of the walls over a long period of time.

The mode of operation of the inflating device,

of either type shown in the drawings, when provided with a passage 15, is the Same as when the spaces 30 or 54 remain vacuum pockets, except that the operating characteristics are modified. There is less resistance to intake movement of the diaphragm, and less force available for the return stroke of the diaphragm. And, strains on the diaphragm are relieved when it is held in distended position during high speed vehicle travel.

Control of the rate at which the device will pump air may be eiected by adjustment of the intake valve, the tension of spring 62, for example, or by predetermining the size of the aperture 64, or by predetermining or adjusting the size of the passage 15, or by two or more such adjustments. 1 Y Y The inflating device may have van intake valve of either type shown in Figures l1 or 3, either an exhaust valve or an aperture 64, either a vacuum space around the air pocket or a similar space with a passage to` breathe to the atmosphere. Any combination of the foregoing alternatev features may be combined in an nflating device of this invention.

If the tire should be excessively under-inflated, the point where there'is nov more relative movement between members I may be passed and actuation of the inflating device will cease.V This is desirable in that excessive wear on the device, by excessive under-inflation, is avoided. Also, members 'l are well below the centers of the side walls of the casing so that, if the tire should become iiat, the length of the connections is such that they will be loose and not torn out. It is not intended to compensate for the condition of an excessively under-inated tire by the device of this invention.

The nut 63 is adjustable on the stem 6l to control the tension of spring 52. thereby to load the valve as may be desired. Byso loading the valve 60, the magnitude of pressure differential across the valve 60 necessary to open the valve, upon intake displacement of diaphragm 48, maybe adjusted to any value desired, within vthe limits essential to proper operation of the device. By regulating the load upon valve 60, the minimum displacement of diaphragm 48, from collapsed position, necessary to effect air intake through valve 69, may be adjusted. Thus, a minimum actuation of diaphragm 48, by relative lateral displacement of pressure members l, is predetermined. From the foregoing, it will be apparent that adjustment of nut 63 on stem 6l predetermin'es the degree of inflation beyond which the device of this invention will no longer operate to inflate the tire, even though some deformation of the tirel casing may cause slight displacement of diaphragm 48, less than the minimum above mentioned.

Certain advantages are inherent inthe location of members 1, in addition to the manner in which those members coact to provide the actuating force for air intake. be stiff, as compared to tire stiffness, t0 convert the iluid pressure into actuating force. Since there are two members, the area of each may be small with consequent little effect on flexing of the tire. Also, when a tire isfully iniiated, some flexing at the tread occurs at road contact, Vbut The members 'I must such flexing causes little or no ilexing'of the side walls. Sincethe members vI are removed from the central part of the tread, and disposed at or adjacent to the sidewalls, little or no movement Vof the tire casing at those regions occurs during flexing of the fully inated tire. `This relieves V the tireV and the inating device of wear a largeV part of the time, and stops operation of the de-V vicewhen the tireis fully'inflated. Also, if a fully inflated tirerbe overloaded, so as Ato cause deformationof the tire, `the resultant movement Vof the sidewalls is not so Vgreat as the deforma'- y Vly deila'ted'while the vehicle was moving. The

structure operates Ywith very little frictional force. makes efficient `use of the actuating forces, and functions with a minimum of wear.

The invention 'has Ybeen described in detail by Vway of illustration. Variations in the details of construction, apparent to one skilled in the art, vf2.5

' of the invention defined in the followingoclaims.

maybeV made without departing from the scope WhatI claim as my invention isas follows:

,i center ofthe tirev tread, a joint between the connections arranged for movement by relative lat-Y Y eral displacement ofthe connections, adiaphragm mounted for displacement in the tire,

meansuniting the diaphragm and joint, a base;

an air pocket arranged between the base and the diaphragm, a vacuum `space around the, air pocketbetween the base and diaphragm, valve means for admittingvair to the pocket, and means for discharging air from the pocket into Y thetre. Y Y

Vfrom the pocket into the tire.

2, In combination, ca' wheel for afvehicle, a pneumatictire mounted on the Wheel, ,connections with the tire arranged in spaced relation in Y,

pocket between the base Vand diaphragmvalve means for admitting'air'to the pocket, avalve mounted in the diaphragm for discharging air '-3. In combination, a wheel `for a vehicle, a pneumatic tire mounted'on the wheel, fconnec` tionsV with the tire arranged in spaced relation in substantially opposite positions relative tothe center of the tire tread, arjointrbetween the connections arranged for movement by relative lat- Yeral displacement of the connections, av diaphragm mounted for displacement in the tire,

f means uniting the diaphragm Vand joint, a base,

an air pocket arranged between the base and the diaphragm, a vacuum space around the air pocket between the base and diaphragm, valve means for admitting air to the pocket, an open Y passage through the diaphragm connecting the air pocket to the space within the tire.

V4:.V In combination, a wheel fora vehicle, a pneumatic tire mounted on the wheel, Vconnections with the tire arranged in spaced relation in substantially opposite positions relative to the Y center of the tire tread, a jointV between the con-V nections arranged forrmovement by relative lateral displacement of the connections, a diaphragm mounted for displacement ,inv the tire,

means uniting the diaphragm and joint, a base, v

an air pocket arranged betweenrthe base and the diaphragm, Valve means for admitting air to the Y pocket,and means for discharging air from the pocket into the tire. f Y' 5. In combination, a wheel for a Vehicle, a pneumatic tire mounted on the wheel, Yconnections with the tire arranged in spaced'relation in substantially opposite positions relative to the center o1V the tire tread, a joint between the con-1 nections varrangedfor movement by relative lateral displacement of Vthe connections, a diaphragm mounted iork displacement `in the tire, means unitingthe diaphragm and joint, a base, an air pocket arranged between the base andthe discharging air from the pocket into the tire.V

6. In combination, a wheel for a' vehicle, a pneumatic tire mountedV on the wheel, connections' with the tire arranged in spaced'relation in substantiallyV opposite Vpositions relative to the Y 1. In combination, a Wheel for a vehicle, a: Vpneumatic tire mounted on the wheelgconnec- Y center of the tire tread, a joint between the connections arranged for movement' by'relative lateral displacement of the connections, a diaphragm mounted forY displacementrin the tire,

means uniting the diaphragm and'V joint, a base,

an airV pocket arrangedVV between the base andV the diaphragm, valve means for'admitting air to the pocket, an open'passage through the diaphragm connecting the air pocket to the space within Vthe tire. Y Y

'7. In, combination, a wheel for a vehicle, a

pneumatic tire mounted on the wheelfconnections with the tire arranged in spaced relationlin substantially opposite positionsy relative to the center of the tire tread, a' joint between rthe connections Varranged for movementfbyrelative lateral Vdisplacement of the connections, a diaphragm mounted for displacement'in the tire,

means uniting the diaphragm andjoint, a base, an air pocket'arranged between the base and the in substantially opposite positions relative to theV centerof the `tire tread, a joint'between therconnections arranged Yfor movement by. relative lateralV displacement. ofV the connections, a dia'- phragm Ymounted for displacementin Vthe'tire, means uniting the diaphragm and joint, a base, an air pocket arranged between the baseoand the diaphragm, a space around the air pocket be,-V tween the base' and diaphragm, said space being Yopen tothe atmosphere, valve means for admitting air tothe pocket, a valve mounted in'the diaphragm for discharging air fromV the pocket into'the tire. f

9. In combination, a wheel for a vehicle, a Y

pneumatic tire "mounted on the wheel, connections with the tire arranged in spaced relation,

in substantially` opposite positionsv relative, to 'the center of the tire tread, a. joint between the connections arranged for movementr by relative lateral displacement of .the connections, laV dia- 20L? diaphragm, valve means for admitting air' to the Y pocket, a valve mounted in the diaphragm forV phragm mounted for displacement 'in the tire, means uniting the diaphragm and joint, a base, an air pocket arranged between the base and the diaphragm, a space around the air pocket between the base and diaphragm, said space being open to the atmosphere, valve means for admitting air to the pocket, an open passage through the diaphragm connecting the air pocket to the space within the tire.

10. An infiating device for a pneumatic tire comprising a base, a diaphragm adapted for displacement to and from the base, an air pocket between the base and diaphragm, a valve to admit air into the pocket from the atmosphere, means for discharging air from the pocket into a tire, connections attached to the -diaphragm and adapted to be secured in a tire at substantially opposite locations relative to the center of the tire tread, said connections being constructed for displacing the diaphragm upon lateral separation by deformation of an under-inflated tire.

ll. An inflating device for a pneumatic tire comprising a valve having a base adapted to be arranged within a tire, a diaphragm mounted on the base for displacement relative to the base, an air pocket arranged between the base and the diaphragm, said valve being set in closed position and operating to admit air into the pocket from the atmosphere upon displacement of the diaphragm, means for passing air from the pocket into a tir-e upon reverse displacement of the diaphragm, connections attached to the diaphragm and adapted to be mounted in a tire at two substantially opposite locations relative to the center of the tire tread, said connections being constructed for air intake displacement of the diaphragm upon relative lateral movement of the connections at the tire.

l2. An inflating device for a pneumatic tire comprising a valve having a base adapted to be arranged within a tire, a diaphragm mounted on the base for displacement relative to the base, an air pocket arranged between the base and the diaphragm, said valve being set in closed position and operating to admit air int-o the pocket from the atmosphere upon displacement of the diaphragm, an open passage from the pocket through the -diaphragm for passing air from the pocket into a tire upon reverse displacement of the diaphragm, connections attached t-o the diaphragm and adapted to be mounted in a tire at two substantially opposite locations relative to the center of the tire tread, said connections being constructed for air intake displacement of the diaphragm upon relative lateral movement of the connections at the tire.

13. In combination, a pneumatic tire for the wheel of a vehicle, an infiating device having means mounted for reciprocatory displacement to eiect inflating action, said means being arranged for actuation in one direction of displacement by fluid pressure within the tire, connections between the means and the tire for displacing the means in the other direction by fluid pressure within the tire, said connections being constructed and arranged relative to the tire for actuating the means only during road contact of that portion of tire adjacent to the connections, the means being free for reverse displacement during the remainder of the revolution of the tire.

14. In combination, a pneumatic tire for the wheel of a vehicle, an inflating device having means mounted for reciprocatory displacement to innate the tire, said means being arranged for displacement in one direction by uid pressure within the tire, connections attached to the means and including a pair of pressure members adapted to receive the fluid pressure within the tire, said pressure members being arranged at substantially opposite locations relative to the center of the tire tread where deformation of the tire, when under-inflated, on road contact will cause relative lateral displacement of the members.

15. In combination, an inating device for a pneumatic tire including a base, a diaphragm mounted for displacement relative to the base,V

an air pocket mounted between the base and the diaphragm, connections attached to the diaphragm including pressure members adapted to be arranged in juxtaposition to the tire casing at substantially opposite locations relative to the center of the tire tread, means for passing air from the air pocket into the tire, and an intake valve arranged to admit air from the atmosphere into the air pocket, said intake valve being adjustable t-o vary the fluid pressure differential required to open the valve.

HOWARD HENRY PARKER. 

